Fluid level sensors are used in a variety of applications that involve detecting a level of fluid within a container. One application of growing significance is in the field of fuel senders for fuel tanks in vehicles. In a conventional arrangement, a fuel sender, more generally known as a type of fluid level sensor, can be disposed within a fuel tank, and may include a float that is mechanically coupled to a main body of the sender unit and that rises and falls along with the fuel level in the container. The float may be rotatably coupled to the main body via a float arm whose angular position corresponds to the float position and therefore the fluid level in the container. Conventionally, an electrical or actively powered sensor is placed within the container as part of the fuel sender and along with the float to sense the angular position of the float arm. Examples of such active sensors include rheostat sensors and inductive-based sensors. Such a sensor is conventionally powered via wiring or an electrical connection, or both, by a power supply external to the container. As a result, installation and use of the fuel sender involves providing power to components (e.g., the electronic sensor) within the container. Further, installation and use of the fuel sender also involves disposing mechanical as well as electrical components within the container, thereby increasing the complexity of installation and any potential repair efforts.
Incorporation of electrical components and providing power thereto into a container can present several design considerations. Conventionally, if the fluid being stored in the container is corrosive or generally reactive, the fuel sender is constructed such that the electrical components and associated electrical conductors are sealed from the fluid by non-reactive materials. Such a construction, including use of such non-reactive materials, can increase the cost and complexity of the fuel sender.
Another design consideration with respect to use of electrical components within a fluid container includes limiting or constraining the voltage or current, or both, supplied to the electrical components. In this way, the power supply may be limited to substantially avoid ignition of potentially flammable vapor within the container. Component selection of the fuel sender is often driven by these considerations.